Efforts to Protect the EnvironmentMost scientists agree that if pollution and other enviro

Efforts to Protect the Environment

Most scientists agree that if pollution and other environmental deterrents (威慑) continue at their present rates, the result will be irreversible (不能倒转的) damage to the ecological cycles and balances in nature upon which all life depends. Scientists ware that fundamental, and perhaps drastic, changes in human behavior. will be required to avert (转移) an ecological crisis.

To safeguard the healthful environment that is essential to life, humans must learn that Earth does not have infinite resources. Earth's limited resources must be conserved and, where possible, reused. Furthermore, humans must devise new strategies that mesh environmental progress with economic growth. The future growth of developing nations depends upon the development of sustainable conservation methods that protect the environment while also meeting the basic needs of citizens.

Many nations have acted to control or reduce environmental problems. For example, Great Britain has largely succeeded in cleaning up the waters of the Thames and other rivers, and London no longer suffers the heavy smogs caused by industrial pollutants. Japan has some of the world's strictest standards for the control of water and air pollution. In Canada, the Department of Commerce has developed comprehensive programs covering environmental contaminants.

In the United States, the Environmental Protection Agency (EPA) was established in 1970 to protect the nation's natural resources. In addition, the U.S. Congress has provided governmental agencies with legislation (立法) designed to protect the environment. Many U.S. states have also established environmental protection agencies. Citizen groups, such as the Sierra Club and the National Audubon Society, educate the public, support environment-friendly legislation, and help assure that federal and state laws are enforced by pointing out violations.

A. Environmentalism in the United States

In the United States the modern environmental movement is rooted in a 19th-century New England philosophical movement called transcendentalism (超验主义), whose leaders included the poet and essayist Ralph Waldo Emerson and the naturalist and author Henry David Thoreau. In their writings, both men expressed a reverence for the natural world, believing that humans and nature shared a divine spirit. Emerson asserted that nature was eternal and capable of recovering from mistreatment at the hands of humans. Thoreau, more protective and pessimistic, has been quoted as saying, "Thank God, men cannot yet fly and lay waste the sky as well as the earth."

Although Emerson and Thoreau wrote eloquently about the value of nature and its spiritual importance to humans, neither of them undertook a systematic analysis of the effects that humans have on their environment. That task was left for 19th-century American diplomat George Perkins Marsh. In 1864 Marsh published Man and Nature; or, Physical Geography as Modified by Human Action, considered the first book to demonstrate that human activity could cause dramatic and irreversible damage to Earth. Marsh explained how some agricultural practices had led to deforestation (采伐森林), loss of wetlands, desertification (the process of land becoming desert), species extinction, and changes in weather patterns.

In the early 20th century, U.S. president Theodore Roosevelt greatly expanded both the national forest and national park systems and created a system of national wildlife refuges. Roosevelt appointed forestry expert Gifford Pinchot as head of the U.S. Forest Service, and together they molded the foundation of the American conservation movement, developing methods for the sustainable use and protection of natural resources. Roosevelt and Pinchot recognized that even the vast natural resources of the United States were not limitless and thus had to be managed carefully, and they believed tha

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